The Experts below are selected from a list of 12063 Experts worldwide ranked by ideXlab platform
Ralf Nauen - One of the best experts on this subject based on the ideXlab platform.
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND:Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms. Copyright © 2010 Society of Chemical Industry
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND: Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms.
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applied aspects of Neonicotinoid uses in crop protection
Pest Management Science, 2008Co-Authors: Alfred Elbert, Matthias Haas, Bernd Springer, Wolfgang Thielert, Ralf NauenAbstract:Neonicotinoid insecticides comprise seven commercially marketed active ingredients: imidacloprid, acetamiprid, nitenpyram, thiamethoxam, thiacloprid, clothianidin and dinotefuran. The technical profiles and main differences between Neonicotinoid insecticides, including their spectrum of efficacy, are described: use for vector control, systemic properties and versatile application forms, especially seed treatment. New formulations have been developed to optimize the bioavailability of Neonicotinoids through improved rain fastness, better retention and spreading of the spray deposit on the leaf surface, combined with higher leaf penetration. Combined formulations with pyrethroids and other insecticides are also being developed with the aim of broadening the insecticidal spectrum of Neonicotinoids and to replace WHO Class I products from older chemical classes. These innovative developments for life-cycle management, jointly with the introduction of generic products, will, within the next few years, turn Neonicotinoids into the most important chemical class in crop protection. Copyright © 2008 Society of Chemical Industry
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Applied aspects of Neonicotinoid uses in crop protection.
Pest management science, 2008Co-Authors: Alfred Elbert, Matthias Haas, Bernd Springer, Wolfgang Thielert, Ralf NauenAbstract:Neonicotinoid insecticides comprise seven commercially marketed active ingredients: imidacloprid, acetamiprid, nitenpyram, thiamethoxam, thiacloprid, clothianidin and dinotefuran. The technical profiles and main differences between Neonicotinoid insecticides, including their spectrum of efficacy, are described: use for vector control, systemic properties and versatile application forms, especially seed treatment. New formulations have been developed to optimize the bioavailability of Neonicotinoids through improved rain fastness, better retention and spreading of the spray deposit on the leaf surface, combined with higher leaf penetration. Combined formulations with pyrethroids and other insecticides are also being developed with the aim of broadening the insecticidal spectrum of Neonicotinoids and to replace WHO Class I products from older chemical classes. These innovative developments for life-cycle management, jointly with the introduction of generic products, will, within the next few years, turn Neonicotinoids into the most important chemical class in crop protection.
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Neonicotinoids—from zero to hero in insecticide chemistry
Pest management science, 2008Co-Authors: Peter Jeschke, Ralf NauenAbstract:In recent years, Neonicotinoids have been the fastest-growing class of insecticides in modern crop protection, with widespread use against a broad spectrum of sucking and certain chewing pests. As potent agonists, they act selectively on insect nicotinic acetylcholine receptors, their molecular target site. The discovery of Neonicotinoids can be considered as a milestone in insecticide research and facilitates greatly the understanding of the functional properties of insect nicotinic acetylcholine receptors. Because of the relatively low risk for non-target organisms and environment, the high target specificity of Neonicotinoid insecticides and their versatility in application methods, this important class has to be maintained globally for integrated pest management strategies and insect resistance management programmes. This review comprehensively describes particularly the origin, structure and bonding as well as associated properties of Neonicotinoid insecticides.
Kevin Gorman - One of the best experts on this subject based on the ideXlab platform.
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND:Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms. Copyright © 2010 Society of Chemical Industry
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND: Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms.
I Denholm - One of the best experts on this subject based on the ideXlab platform.
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mutation of a nicotinic acetylcholine receptor β subunit is associated with resistance to Neonicotinoid insecticides in the aphid myzus persicae
BMC Neuroscience, 2011Co-Authors: Chris Bass, I Denholm, Alin M Puinean, Melanie Andrews, Penny Cutler, Miriam Daniels, Jan Elias, Verity Laura Paul, Andrew J Crossthwaite, Linda M FieldAbstract:Background: Myzus persicae is a globally important aphid pest with a history of developing resistance to insecticides. Unusually, Neonicotinoids have remained highly effective as control agents despite nearly two decades of steadily increasing use. In this study, a clone of M. persicae collected from southern France was found, for the first time, to exhibit sufficiently strong resistance to result in loss of the field effectiveness of Neonicotinoids. Results: Bioassays, metabolism and gene expression studies implied the presence of two resistance mechanisms in the resistant clone, one based on enhanced detoxification by cytochrome P450 monooxygenases, and another unaffected by a synergist that inhibits detoxifying enzymes. Binding of radiolabeled imidacloprid (a Neonicotinoid) to whole body membrane preparations showed that the high affinity [3H]-imidacloprid binding site present in susceptible M. persicae is lost in the resistant clone and the remaining lower affinity site is altered compared to susceptible clones. This confers a significant overall reduction in binding affinity to the Neonicotinoid target: the nicotinic acetylcholine receptor (nAChR). Comparison of the nucleotide sequence of six nAChR subunit (Mpa1-5 and Mpb1) genes from resistant and susceptible aphid clones revealed a single point mutation in the loop D region of the nAChR b1 subunit of the resistant clone, causing an arginine to threonine substitution (R81T). Conclusion: Previous studies have shown that the amino acid at this position within loop D is a key determinant of Neonicotinoid binding to nAChRs and this amino acid change confers a vertebrate-like character to the insect nAChR receptor and results in reduced sensitivity to Neonicotinoids. The discovery of the mutation at this position and its association with the reduced affinity of the nAChR for imidacloprid is the first example of field-evolved target-site resistance to Neonicotinoid insecticides and also provides further validation of exisiting models of Neonicotinoid binding and selectivity for insect nAChRs.
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND: Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms.
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND:Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms. Copyright © 2010 Society of Chemical Industry
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resistance of insect pests to Neonicotinoid insecticides current status and future prospects
Archives of Insect Biochemistry and Physiology, 2005Co-Authors: Ralf Nauen, I DenholmAbstract:The first Neonicotinoid insecticide introduced to the market was imidacloprid in 1991 followed by several others belonging to the same chemical class and with the same mode of action. The development of Neonicotinoid insecticides has provided growers with invaluable new tools for managing some of the world's most destructive crop pests, primarily those of the order Hemiptera (aphids, whiteflies, and planthoppers) and Coleoptera (beetles), including species with a long history of resistance to earlier-used products. To date, Neonicotinoids have proved relatively resilient to the development of resistance, especially when considering aphids such as Myzus persicae and Phorodon humuli. Although the susceptibility of M. persicae may vary up to 20-fold between populations, this does not appear to compromise the field performance of Neonicotinoids. Stronger resistance has been confirmed in some populations of the whitefly, Bemisia tabaci, and the Colorado potato beetle, Leptinotarsa decemlineata. Resistance in B- and Q-type B. tabaci appears to be linked to enhanced oxidative detoxification of Neonicotinoids due to overexpression of monooxygenases. No evidence for target-site resistance has been found in whiteflies, whereas the possibility of target-site resistance in L. decemlineata is being investigated further. Strategies to combat Neonicotinoid resistance must take account of the cross-resistance characteristics of these mechanisms, the ecology of target pests on different host plants, and the implications of increasing diversification of the Neonicotinoid market due to a continuing introduction of new molecules.
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resistance of insect pests to Neonicotinoid insecticides current status and future prospects
Archives of Insect Biochemistry and Physiology, 2005Co-Authors: Ralf Nauen, I DenholmAbstract:The first Neonicotinoid insecticide introduced to the market was imidacloprid in 1991 followed by several others belonging to the same chemical class and with the same mode of action. The development of Neonicotinoid insecticides has provided growers with invaluable new tools for managing some of the world's most destructive crop pests, primarily those of the order Hemiptera (aphids, whiteflies, and planthoppers) and Coleoptera (beetles), including species with a long history of resistance to earlier-used products. To date, Neonicotinoids have proved relatively resilient to the development of resistance, especially when considering aphids such as Myzus persicae and Phorodon humuli. Although the susceptibility of M. persicae may vary up to 20-fold between populations, this does not appear to compromise the field performance of Neonicotinoids. Stronger resistance has been confirmed in some populations of the whitefly, Bemisia tabaci, and the Colorado potato beetle, Leptinotarsa decemlineata. Resistance in B- and Q-type B. tabaci appears to be linked to enhanced oxidative detoxification of Neonicotinoids due to overexpression of monooxygenases. No evidence for target-site resistance has been found in whiteflies, whereas the possibility of target-site resistance in L. decemlineata is being investigated further. Strategies to combat Neonicotinoid resistance must take account of the cross-resistance characteristics of these mechanisms, the ecology of target pests on different host plants, and the implications of increasing diversification of the Neonicotinoid market due to a continuing introduction of new molecules. Arch. Insect Biochem. Physiol. 58:200–215, 2005. © 2005 Wiley-Liss, Inc.
Nikos Karatolos - One of the best experts on this subject based on the ideXlab platform.
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND:Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms. Copyright © 2010 Society of Chemical Industry
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incidence and characterisation of resistance to Neonicotinoid insecticides and pymetrozine in the greenhouse whitefly trialeurodes vaporariorum westwood hemiptera aleyrodidae
Pest Management Science, 2010Co-Authors: Nikos Karatolos, Ralf Nauen, I Denholm, Martin S Williamson, Kevin GormanAbstract:BACKGROUND: Trialeurodes vaporariorum (Westwood), also known as the greenhouse whitefly, is a serious pest of protected vegetable and ornamental crops in most temperate regions of the world. Neonicotinoid insecticides are used widely to control this species, although resistance has been reported and may be becoming widespread. RESULTS: Mortality rates of UK and European strains of T. vaporariorum to a range of Neonicotinoids and pymetrozine, a compound with a different mode of action, were calculated, and significant resistance was found in some of those strains. A strong association was found between Neonicotinoids and pymetrozine, and reciprocal selection experiments confirmed this finding. Expression of resistance to the Neonicotinoid imidacloprid and pymetrozine was age specific, and resistance in nymphs did not compromise recommended application rates. CONCLUSION: This study indicates strong parallels in the phenotypic characteristics of Neonicotinoid resistance in T. vaporariorum and the tobacco whitefly Bemisia tabaci Gennadius, suggesting possible parallels in the underlying mechanisms.
Kazuhiko Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Neonicotinoid Insecticides: Molecular Targets, Resistance, and Toxicity.
Annual review of pharmacology and toxicology, 2020Co-Authors: Kazuhiko Matsuda, Makoto Ihara, David B. SattelleAbstract:Neonicotinoids have been used to protect crops and animals from insect pests since the 1990s, but there are concerns regarding their adverse effects on nontarget organisms, notably on bees. Enhanced resistance to Neonicotinoids in pests is becoming well documented. We address the current understanding of Neonicotinoid target site interactions, selectivity, and metabolism not only in pests but also in beneficial insects such as bees. The findings are relevant to the management of both Neonicotinoids and the new generation of pesticides targeting insect nicotinic acetylcholine receptors.
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Neonicotinoids: molecular mechanisms of action, insights into resistance and impact on pollinators.
Current opinion in insect science, 2018Co-Authors: Makoto Ihara, Kazuhiko MatsudaAbstract:Neonicotinoids are insecticides that target insect nicotinic acetylcholine receptors (nAChRs), exhibiting high selective toxicity to insects over vertebrates and good systemic activity in crop plants. For these reasons, Neonicotinoids currently make up ∼30% of insecticide sales worldwide. However, due to their adverse impact on pollinators such as honey bees and bumble bees, Neonicotinoids are being banned from the EU, and other countries may follow. It is therefore crucial to understand the mechanism underlying Neonicotinoid actions on pollinators as well as on the nAChRs of pests, with a view to understanding their selectivity. Here we review the molecular mechanisms of Neonicotinoid actions at an atomic level, through structural and resistance mechanism studies and propose relevant research topics for further studies on the future of pest management.
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A hypothesis to account for the selective and diverse actions of Neonicotinoid insecticides at their molecular targets, nicotinic acetylcholine receptors: catch and release in hydrogen bond networks
Invertebrate Neuroscience, 2007Co-Authors: Makoto Ihara, David B. Sattelle, Masaru Shimomura, Miki Akamatsu, Chiharu Ishida, Hisashi Nishiwaki, Kazuhiko MatsudaAbstract:The low mammalian toxicity of Neonicotinoid insecticides has been shown to be attributable, at least in part, to their selective actions on insect nicotinic acetylcholine receptors (nAChRs). There are multiple nAChRs in insects and a wealth of Neonicotinoid chemicals. Studies to date have discribed a wide range of effects on nAChRs, notably partial agonist, super agonist and antagonist actions. Both the diversity of the Neonicotinoid actions and their selectivity for insect over vertebrate nAChRs are the result of physicochemical and steric interactions at their molecular targets (nAChRs). In such interactions, the formation and breakage of hydrogen bond (HB) networks plays a key role. Therefore the loss or gain of even a single HB resulting from either structural changes in Neonicotinoids, or the amino acid sequence of a particular nAChR subunit, could result in a drastic modification of Neonicotinoid actions. In addition to the amino acid residues, the backbone carbonyl of nAChRs may also be involved in the formation of HB networks with Neonicotinoids.
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Neonicotinoids show selective and diverse actions on their nicotinic receptor targets electrophysiology molecular biology and receptor modeling studies
Bioscience Biotechnology and Biochemistry, 2005Co-Authors: Kazuhiko Matsuda, Makoto Ihara, Masaru Shimomura, Miki Akamatsu, David B. SattelleAbstract:Neonicotinoid insecticides, which act selectively on insect nicotinic acetylcholine receptors (nAChRs), are used worldwide for insect pest management. Studies that span chemistry, biochemistry, molecular biology, and electrophysiology have contributed to our current understanding of the important physicochemical and structural properties essential for Neonicotinoid actions as well as key receptor residues contributing to the high affinity of Neonicotinoids for insect nAChRs. Research to date suggests that electrostatic interactions and possibly hydrogen bond formation between Neonicotinoids and nAChRs contribute to the selectivity of these chemicals. A rich diversity of Neonicotinoid-nAChR interactions has been demonstrated using voltage-clamp electrophysiology. Computational modeling of nAChR-imidacloprid interaction has assisted in the interpretation of these results.
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Mechanism of selective actions of Neonicotinoids on insect nicotinic acetylcholine receptors
2005Co-Authors: Kazuhiko Matsuda, David B. SattelleAbstract:Neonicotinoid insecticides act selectively on insect nicotinic acetylcholine receptors (nAChRs), but little is known about the mechanism of selectivity. To elucidate the mechanism, structural features of Neonicotinoids and insect nAChRs contributing to this selectivity have been examined. Using molecular-oribital calculations, electrostatic interactions and hydrogen-bond formation of Neonicotinoids with insect nAChRs were postulated to contribute to the selectivity of Neonicotinoid-nAChR interactions. Also, the use of voltage-clamp electrophysiology combined with molecular biology showed that replacement of the vertebrate a4 subunit in the α4β2 nAChR by Drosophila a subunits and mutation to basic residues of an amino acid in loop D of the a7 nAChR enhanced Neonicotinoid sensitivity of the nAChRs. These findings suggest important roles for a and non-a subunits in the selective actions of Neonicotinoids on insect nAChRs.